1. Field of the Invention
The present invention relates to an oxynitride phosphor that has a JEM phase as a main component and a semiconductor light-emitting device using the oxynitride phosphor. Specifically, the invention relates to a semiconductor light-emitting device that can be used for a backlight light source for liquid crystal displays, a portable telephone, a portable information terminal, an LED (light-emitting diode) display device used for indoor and outdoor advertisements, an indicator for various kinds of portable units, or a light source for an illumination switch or OA (office automation) units. The invention particularly relates to a semiconductor light-emitting device where an oxynitride phosphor converts an wavelength of emission from a semiconductor light-emitting element to use as a light source and an oxynitride phosphor suitable for the semiconductor light-emitting device.
2. Description of the Background Art
A semiconductor light-emitting device is small in size, less in the power consumption, and stable in high brightness emission. Accordingly, it is in wide use as a light source of various kinds of display devices. Furthermore, the semiconductor light-emitting device is also used as a light source for reading and/or writing information in various kinds of information processors. So far, as a semiconductor light-emitting element used in a semiconductor light-emitting device that emits visible light, depending on forming conditions of a semiconductor material that is used in an emitting layer, ones that emit light from red to purple have been put into practical use.
With the semiconductor light-emitting elements that emit various emission colors, for instance, with light-emitting diodes (LED) each of which emits one of three primary colors of red, green and blue, an image display device is put into practical use.
Furthermore, in for instance Japanese Patent Laying-Open No. 10-242513, a semiconductor light-emitting device where a semiconductor light-emitting element that emits short wavelength visible light from blue to purple and a phosphor are combined and thereby emission of the semiconductor light-emitting element and light that is wavelength-converted by the phosphor are mixed to obtain white light is disclosed.
Still furthermore, in Japanese Patent Laying-Open No. 10-163535, a semiconductor light-emitting device where a semiconductor light-emitting element that emits blue or bluish purple light is combined with one kind or two kinds of phosphors is disclosed. Here, the phosphor is selected so that emission color of the semiconductor light-emitting element and emission color of the phosphor may be mutually complementary colors to emit pseudo-white light.
Furthermore, in Japanese Patent Laying-Open No. 10-012925, a semiconductor light-emitting device that is provided with a semiconductor light-emitting element that emits ultra-violet light and near ultra-violet light and a phosphor is disclosed. The semiconductor light-emitting element is a semiconductor light-emitting element that normally emits blue light and, when a pulse-like large current is flowed to the semiconductor light-emitting element, emits ultra-violet light or near ultra-violet light. Here, a technology where only by changing a kind of the phosphor, with only one kind of semiconductor light-emitting element, a plurality of colors can be emitted is disclosed.
Still furthermore, in Japanese Patent Laying-Open No. 09-153644, a dot matrix type display device that is provided with an emitting layer that is formed by use of a III group nitride semiconductor and emits ultraviolet light having a peak wavelength of 380 nm and three kinds of phosphor layers that receive ultraviolet light from the emitting layer to respectively emit lights of three primary colors of red, green and blue is disclosed.
Furthermore, in Japanese Patent Laying-Open No. 2002-017100, a semiconductor light-emitting device where a semiconductor light-emitting element that emits light having a wavelength in the range of 390 nm to 420 nm and a phosphor that is excited by the emission from the semiconductor light-emitting element are used to emit white light is disclosed. Here, since the semiconductor light-emitting element emits light low in the human visual sensitivity, a variation of the emission intensity or emission wavelength of the semiconductor light-emitting element seems to hardly affect on the color tone. Furthermore, light having a wavelength in the range of 390 to 420 nm hardly damages device constituent components such as a resin in which the phosphor is dispersed. Still furthermore, in general, ultraviolet light variously adversely affects on human bodies; however, since light having a wavelength of 390 nm or more is used, leaked excitation light does not adversely affect. In this case, as the phosphor that can be excited by light having a wavelength in the range of 390 nm to 420 nm to luminesce, various oxide and sulfide phosphors are being used.
As the phosphor that is used in the above-mentioned applications, other than oxide and sulfide phosphors, recently, examples of oxynitride and nitride phosphors are disclosed in Japanese Patent Laying-Open Nos. 2002-363554 and 2003-206481. The phosphors can be excited by light having a wavelength in the range of 390 nm to 420 nm and have high emission efficiency. Furthermore, these phosphors are high in the stability and hardly exhibit variation of the emission efficiency when an environmental temperature varies. That is, the above-mentioned phosphors have excellent characteristics in many cases.